The field of this invention is geographic location referencing systems.
A geographic location system has an addressing scheme that allows a location to be uniquely addressed. Several systems are well known and currently in use, such as geodetic latitude and longitude, Universal Transverse Mercator (UTM), Military Grid Reference System (MGRS), World Geographic Reference System (GEOREF), Maidenhead, Trimble Grid, Trimble Atlas, and Thomas Brothers Detail. These known systems can generally be divided into two categories: global and local. The global systems, such as geodetic latitude and longitude, UTM, MGRS, GEOREF, Maidenhead, and Trimble Grid, use a scheme that subdivides the globe into areas of increasing resolution, until a particular location is properly identified. Thus each location address is referenced to the global system, allowing for the easy comparison of two location addresses. However, the addresses tend to be complicated, cumbersome, and unrelated to the real world, increasing the complexity of these systems.
The local systems, such as Thomas Brothers paper mapping systems, provide a technique that assigns location addresses based on association with a geographic region or physical map pages, with every location identified with only one region. This type of local system is easier to use for local location information in connection with a physical map, but is difficult to use with respect to a more global or electronic systems, as there is no simple way to convert a local address into a global address, and the local address is not recognized in the global systems.
Location technology has been significantly impacted by the wide availability of Global Positioning Systems (GPS), which are operated by the United States Department of Defense to provide worldwide navigation, position location, and precision timing services. GPS comprises a global network of satellites that interact with a controller coupled to a GPS receiver, allowing the controller to precisely determine its location. This location is typically output from the GPS receiver as latitude and longitude numbers, which are cumbersome for users to understand and use. A GPS receiver is sometimes coupled with additional capability that allows the raw latitude/longitude numbers to be converted into a more useful and usable format. See, e.g., Sprague et al., U.S. Pat. No. 5,422,814; Inoue, U.S. Pat. No. 5,289,195; and Yamashita, U.S. Pat. No. 5,471,392. However, even with these enhancements, a problem with these systems is that they are still difficult to use by persons who are unskilled in the use of location referencing systems. Another problem is that these systems are unwieldy because they still retain their global character. Thus, what is needed is a referencing system that can be used with a minimum amount of reading, scrolling, and searching, and with a limited number of keystrokes for data entry. Also needed is a user-friendly, truly local addressing system that is easily convertible to a known global system for wide-range concerns.